If you receive errors when trying to unprotect a .cst, extract the Xtras folder and keep the the Xtras folder next to the recover-cct program.
(from recover-dir.com)
What is recover-cct?
recover-cct is an application that allows you to recover files generated with Director (movies and cast) and that have been protected, and in this way open these files with your original program.
Do you say that it recovers protected files?
recover-cct releases the files that have been protected with Director so they can be re-edited. Because of how Director performs this protection, the Lingo code that has been written will never be recovered, although in case
there is one, it will still be executed without being able to edit or visualize this Lingo code.
Does it also recover protected Flash files?
No, recover-cct does not check out protected Flash files or executables generated with Flash. It is also not expected that recover-cct will do so in future versions.
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Note: The "cst_to_hack.cst" file is whatever .cct you want to recover. You supply the .cct yourself.